The consumption of diesel and jet fuels in the United States is estimated to range from between 20 and around 50 billion gallons per year. While the integration of biofuels into this market has been growing, currently biodiesel represents less than 1% of the total U.S. diesel market and nearly all aviation fuels are currently derived from fossil fuel sources. As with many forms of fossil fuels, a desire exists to replace the use of these finite and non-renewable resources with renewable resources such as those based upon biomass. Biofuel based diesel and jet fuels are not only in accordance with the U.S. government's vision for future fuels but also encouraged by the American airline industry.
Bio-fuels can come from a variety of sources including bio-oils derived from various based sources. However, most bio-oils are complex microemulsions of aqueous and non-aqueous phases containing hundreds of different organic and inorganic compounds. Oxygenated hydrocarbons found in bio-oils can include esters, acids, aldehydes, alcohols, ketones, sugars, and various phenol derivatives. These reactive species in bio-oils complicate storage, transportation, and downstream processing because secondary reactions can cause condensation and polymerization which increase the viscosity of the bio-oil and form problematic solids. This in turn leads to other problems including coking which can render catalysts intended to treat these materials ineffective. Bio-oils can also contain organic acids such as acetic acid and formic acid as well as phenolics that can cause corrosion and damage the infrastructure of conventional processing systems. In view of the types of complexities and problems various methods are sought to remove these reactive functionalities to improve bio-oil stability.
Stabilization of bio-oils by hydrogenation is typically performed using pressurized hydrogen (H2) at elevated temperatures. However, bio-oils lack thermal stability and, upon break down, compounds in bio-oils form coke which block catalyst sites and plugs reactors during treatment at elevated temperatures. Among the plugging items and undesired materials that arise in bio-oil preprocessing are cyclic hydrocarbons. Bio-fuels obtained from typical direct liquefaction routes such as fast pyrolysis, catalytic fast pyrolysis, and hydrothermal liquefaction typically create a generally high number of cyclic carbon chains, including aromatics like alkylbenzenes and cycloparaffins such as alkylcyclohexanes. Converting these types of products into fuel-type chemicals can make the insertion of such a treated bio-oil into a standard fuel delivery or refining system is one potential way of increasing the use and application of complex bio-oils and enhances the likelihood of their eventual adaptation into the diesel and jet markets. The present disclosure provides significant advance in this field by providing a path toward such a conversion.